Polysilane is one of the "hot" materials in current research and development because of its peculiar structure and interesting physical and chemical properties. One problem in developing this material is preparation method. The common method which utilizes Wults coupling reaction by alkali metal requires a reaction temperature as high as about 110.degree. C. and very drastic reaction conditions. This synthetic problem limits the substituents on polysilane polymers. The other known preparation methods are not very effective to synthesize polysilane polymers having a high molecular weight.
As for the preparation of polysilane copolymers, in turn, copolymers of polysilane with polythiophene and polyphenylene were reported although copolymers having a high molecular weight were not available. Most methods for the preparation of copolymers of polysilane with ethylene, acetylene, and phenylene utilize either Wults coupling reaction or lithium acetylide and thus require drastic reaction conditions. It is known in the art to prepare high polymers through ring-opening reaction under mild conditions, for example, using benzosilacyclobutene as proposed by Shiina et. al. and using tetrasilacycloocta-1,5-diine as proposed by West et. al. These methods are able to introduce only disilanyl unit in the polymers. It is thus desired to introduce a longer polysilane chain for obtaining copolymers possessing more the character of polysilane.